Early blight

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Minor Pest Title

Early blight (Alternaria solani)

Minor Pest Description

Leaf spots of early blight are circular, up to 12 mm in diameter, brown, and often show a circular pattern.


On the potato tuber early blight results in surface lesions that appear a little darker than adjacent healthy skin. Lesions are usually slightly sunken, circular or irregular, brown and vary in size up to 1-2 cm in diameter. There is usually a well defined and sometimes slightly raised margin between healthy and diseased tissue. Internally, the tissue shows a brown to black corky, dry rot, usually not more than 6 mm. Deep cracks may form in older lesions.


Early blight thrives best under warm wet conditions.



Minor Pest What to do.
  • Use certified disease-free seeds
  • Practise rotation with non-solanaceaous crops.
  • Practise good field hygiene. Remove infected leaves during the growing season and discard all badly infected potato plant debris at the end of each season.
  • Avoid overhead irrigation and lay down a thick organic mulch to prevent soil splashing onto lower leaves.
Minor Pest Position
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Pest Type
Common names; Early blight, Alternaria blight, dry blight, leaf spots, seedling blight, damping-off, collar rot, hard-rot of fruits
Host Plants
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